This is our third blogpost in our off-season spring cleaning series. To recap, we’re in the process of shutting a number of products which haven’t had the impact we’d hoped for, integrating others as features into our broader product efforts, and ending several which have shown us a different path forward. Overall, our aim is to build a simpler, more intuitive, truly beautiful Google user experience. In terms of the details, here is the latest update:

Google Bookmarks Lists—This is an experimental feature for sharing bookmarks and collaborating with friends, which we’re going to end on December 19, 2011. All bookmarks within Lists will be retained and labeled for easier identification, while the rest of Google Bookmarks will function as usual. As Lists was an English-only feature, non-English languages will be unaffected.

Google Friend Connect—Friend Connect allows webmasters to add social features to their sites by embedding a few snippets of code. We're retiring the service for all non-Blogger sites on March 1, 2012. We encourage affected sites to create a Google+ page and place a Google+ badge on their site so they can bring their community of followers to Google+ and use new features like Circles and Hangouts to keep in touch.

Google Gears—In March we said goodbye to the Gears browser extension for creating offline web applications and stopped supporting new browsers. On December 1, 2011, Gears-based Gmail and Calendar offline will stop working across all browsers, and later in December Gears will no longer be available for download. This is part of our effort to help incorporate offline capabilities into HTML5, and we’ve made a lot of progress. For example, you can access Gmail, Calendar and Docs offline in Chrome.

Google Search Timeline—We’re removing this graph of historical results for a query. Users will be able to restrict any search to particular time periods using the refinement tools on the left-hand side of the search page. Additionally, users who wish to see graphs with historical trends for a web search can use google.com/trends or google.com/insights/search/ for data since 2004. For more historical data, the "ngram viewer" in Google Books offers similar information.

Google Wave—We announced that we’d stopped development on Google Wave over a year ago. But as of January 31, 2012, Wave will become read-only and you won’t be able to create new ones. On April 30 we will turn it off completely. You’ll be able to continue exporting individual waves using the existing PDF export feature until the Google Wave service is turned off. If you’d like to continue using this technology, there are a number of open-source projects, including Apache Wave and Walkaround.

Knol—We launched Knol in 2007 to help improve web content by enabling experts to collaborate on in-depth articles. In order to continue this work, we’ve been working with Solvitor and Crowd Favorite to create Annotum, an open-source scholarly authoring and publishing platform based on WordPress. Knol will work as usual until April 30, 2012, and you can download your knols to a file and/or migrate them to WordPress.com. From May 1 through October 1, 2012, knols will no longer be viewable, but can be downloaded and exported. After that time, Knol content will no longer be accessible.

Renewable Energy Cheaper than Coal (RE<C)—This initiative was developed as an effort to drive down the cost of renewable energy, with an RE<C engineering team focused on researching improvements to solar power technology. At this point, other institutions are better positioned than Google to take this research to the next level. So we’ve published our results to help others in the field continue to advance the state of power tower technology, and we’ve closed our efforts. We will continue our work to generate cleaner, more efficient energy—including our on-campus efforts, procuring renewable energy for our data centers, making our data centers even more efficient and investing more than $850 million in renewable energy technologies.